U.S. Navy fire zone doors are utilized in fire zone boundaries where egress through bulkheads is needed but watertight integrity is not required. These doors must be as close to fume-tight as possible. Typically the doors are formed from a hollow panel filled with a heat insulating material that reduces heat transfer from one side of the door panel to the other during a fire. Gaskets are typically used around the opening of the door, in order to approach a fume-tight status.
Current methods used to prevent the spread of fire and the passage of smoke through doorways include the use of gaskets that have a core made of silicone rubber, covered with a stainless steel wire reinforced fiberglass yarn that is over-coated with silicone rubber. The gasket is attached to a gasket retainer. This prior art gasket tends to be very rigid and difficult to install due to irregularities that typically exist in the bulkhead in which the frame is installed. Often it is difficult to obtain a continuous seal around the perimeter of the door opening, thus defeating the purpose of obtaining a fume-tight seal.
A softer less rigid gasket would improve the ability to seal the doorway, compensating for any irregularities in the bulkhead in which the fire zone doors are installed. As outlined in U.S. Pat. No. 5,553,871, a softer rubber, the type ZZ-R-765 gasket was developed for providing a watertight seal. Softer rubber based products, as taught in U.S. Pat. No. 5,553,871, would allow for easier installation, however softer rubber based products are not suited to withstand the temperature requirements in working conditions for prolonged periods of time. Consequently, there is a need for a more pliable gasket arrangement that could withstand the rigors associated with a fire.